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Improved blood doping detection protects sport and athletes

9 August 2012

Blood doping has affected many high profile sports events like the Tour de France. [Image: Flickr/Josh Hallett]

The practice of blood doping has been widespread but notoriously difficult to detect among Olympic athletes since the 1980s. Improvements to the accuracy and relevance of the test for blood doping by a University of Sydney researcher could soon put an end to finger pointing, weak excuses and suspicion in elite sports.

Dr Corinne Caillaud of the University's Faculty of Health Sciences is working on a project to determine whether current methods to detect performance-enhancing hormone Erythropoetin (EPO) may incorrectly report false positive cases, particularly in the context of the intense physical exercise of elite athletes at top-level competitions such as the Olympics.

EPO is a hormone used by endurance athletes to boost red blood cell production to increase oxygen transport around the body and improve aerobic performance. Use of the drug exploded in popularity following the 1998 Tour de France, when it was found in the hotel rooms and support vehicles of competing teams.

"Blood doping can be achieved either via blood transfusion or EPO injections. The performance enhancing material is the blood itself, or a hormone (EPO) that is naturally produced by the body. This is why it can be so difficult to detect," says Dr Caillaud.

One of first steps taken by anti-doping bodies to fight EPO abuse was to set a 'non-participation threshold', which meant that no athlete could present to competition with a volume percentage of red blood cells, or 'haematocrit', higher than 51. The average haematocrit for an adult male is 42 to 51 percent.

Dr Caillaud believes this threshold was both unfair for athletes with a naturally high haematocrit and inefficient to stop doping.

The more efficient testing methods currently used by the World Anti-Doping Agency include both urine detection of recombinant EPO and a 'blood passport', which keeps a long-running, continuous record of athletes' blood test results to detect inconsistencies and evidence of blood manipulation.

However, there is still uncertainty over false positives produced using the current testing methods. Dr Caillaud's research tackles the question of blood and urine tests that return false positive cases, particularly a common justification that strenuous, prolonged exercise in hot conditions can produce false positives.

"We need more data on the impact of strenuous physical exercise on the critical markers used to detect blood doping," she says.

"Athletes and officials need to be able to trust the detection process and be reassured no false positive results will be returned. While you or I would barely notice the changes EPO makes to our bloodstreams, when you're running, swimming or cycling long distances it can make the difference between winning and losing," Dr Caillaud says.

In a clinical trial, Dr Caillaud examined EPO levels in elite cyclists training in very hot conditions over a number of days for nine weeks.

Preliminary results from her work have so far produced no evidence of any relationship between intense exercise in hot weather and false positive results, which could provide much-needed credibility and authority for the World Anti-Doping Agency's current methods.

Dr Caillaud's work responds to an alarming lack of research on the impact of physical exercise on markers of EPO abuse in the context of elite sports.

"It's vital that we continue to research drug abuse in sport to determine the real effect of drugs on human performance, develop new detection methods and most importantly protect the health of the athletes."